Effective, reliable, safe, and economical packaging of bulk material products into containers for handling, transport, and storage have been concerns for many years to the packaging and transport industries. Bulk products requiring such packaging vary widely from semisolids such as ketchup and other food items, to granular materials such as beans, peas, grains, rice, salt, flour, sugar, dry chemicals, dry cementitious products, animal feeds, fertilizers, soap, and other such items, to liquid materials such as syrups, milk, juices, glues, inks, paints, resins, chemicals, and the like. Since such materials have a tendency to move or flow, containment of them for shipment handling and storage raises many challenges. While the shapes and configurations of containers for such bulk products vary, a commonly used container configuration has been a drum-type container that can be readily transported by truck, rail, or ship and that can be easily handled during transport and at a final destination, such as at a processing or manufacturing facility, by hand or by readily available equipment such as a forklift, crane, or hand truck. The flowing nature and weight of bulk products present unique packaging issues for a drum container. A popular packaging industry standard drum-type container commonly used for transporting bulk materials is the 55-gallon drum, which is easy to handle and move and which is conveniently arrangeable on industry standard sized pallets. Movement or shifting of contained bulk materials during transport can cause deformation of the drum container that can result in load shifting and instability and possible bursting of the drum, often with enough force to damage or destroy the drum container. The result is loss or damage to drum container contents and undue clean-up and environmental concerns. Besides the strength requirements for containing a bulk material, the container must be designed for additional strength, stability, and reliability if the containers are stacked upon each other during storage or shipment.
While the 55-gallon drum container has been a favorite size and configuration in the packaging industry, and while the preferred embodiments of the present invention will be described primarily in view of the 55-gallon drum industry standard, it should be understood that this invention is not limited to a 55-gallon container or even to a drum shaped container. Those skilled in the art will recognize that the principals of this invention apply to containers of both larger and smaller containment sizes and to containers of varied configurations, geometric shapes, and profiles. Further, while the preferred embodiments of the invention described herein will use specific materials that are suitable for containing certain bulk materials, those skilled in the an will recognize that the principles of this invention apply to the use of other container materials not specifically referred to in this specification. Further, while the preferred embodiments described herein may use polyethylene or polypropylene liners that fit within the drum type container described and are compatible with or suitable for the bulk material being contained for preventing contamination of the material or, in the case of a liquid, for containing the liquid, the invention is not limited to the use of such liners, or to any particular material described for such liners.
The packaging industry has primarily used five 55-gallon bulk material containment approaches. They will be referred to herein as: (1) the “corrugated” drum containment approach: (2) the “woven fabric” drum containment approach; (3) the “fiber” drum containment approach, (4) the “plastic” drum containment approach; and (5) the “metal” drum containment approach.
Corrugated 55-gallon drum containers are typically manufactured from corrugated cardboard panels that are scored so as to define six or eight vertical wall panels and also the bottom of the container. The ability of a corrugated drum container to handle a wide variety of weight and product consistency requirements is addressed by using different strength grades of corrugated board materials and/or by increasing the wall thickness of the corrugated board material by gluing corrugated sheets together or by inserting a corrugated material sleeve into the outer drum wall perimeter. The price of corrugated 55-gallon drum containers significantly increases with increased wall thickness and/or higher grade or quality corrugated materials. If the drum container board wall strength and/or thickness is reduced in order to cut costs, the contained bulk material pressure exerted against the thinner drum container walls generally causes the drum container wall to bulge outwardly and can result in the drum container having a marginal safety factor that can lead to costly drum container failures during shipment Corrugated drum containers that are subjected to high-humidity and moisture environments can cause the corrugated board material to weaken since they are manufactured from paper. Such high-humidity environments can be found in warehouses or when the container is transported by boat. This problem can be mitigated by using moisture or water resistant coatings or adhesives when the drum containers are manufactured. However, usefulness of the coatings are limited since the base material of the container is paper. Further, such treatments significantly add to the cost of the corrugated drum container. Corrugated drum containers are also subject to damage caused by movement of the container. It is common to move drum containers by hand (without mechanical means) by first tipping the drum container's body into an angled vertical position and then twisting or rolling the drum container along its lower edge to a desired location. The bottom of the corrugated drum container has corners that are defined by the spaces between the vertical scored drum wall panels, rather than a curved circular configuration. As a person rolls the drum to move the container, the weight of the container's contents can crush the container's lower angled corners, compromising the strength and reliability of the container. The unused corrugated containers are generally shipped in collapsed, unassembled form and require less space to ship and store than rigid containers, thereby reducing shipping and storage costs. Further, since the container materials are primarily made from paper, the majority of the corrugated container can be and is recycled. However, used corrugated containers are generally recollapsible and can be reused if desired.
In the woven fabric drum containment approach, the bulk material container is made from a woven fabric material that is flexible, collapsible, recyclable, and reusable. Various fabrics such as woven polypropylene and PVC coated fabrics are used and have various fabric weights and utilize various sewing methods, depending on the required strength for the container and its desired safety factor. The woven fabric containment approach uses bags typically used for transporting large quantities (e.g., 2,000 lbs. or more) of bulk material, and are generally referred to as flexible intermediate bulk containers (FIBC's) or bulk bags. However, the woven fabric containers also are made in smaller sizes such as the 55-gallon drum size. The fabric material has outstanding strength and safety factor ratios as compared to the weight of the contained bulk material. For example, an FIBC bag configured to hold a bulk material weighing 2,000 lbs. may have a strength rating capable of holding up to 10,000 lbs. of material-a safety factor ratio of 5:1 The woven fabric container has lifting handles, in the nature of sewn-in slings that can be engaged by a forklift to lift and move the container. The fabric containers can be designed with various shaped tops suitable for filling, and can have a solid bottom or a bottom with a sewn-in discharge spout configured for discharge of the container contents through the bottom of the container. The bulk material can be directly inserted into the woven fabric container, or a polyethylene or polypropylene liner can first be inserted into the woven fabric bag to isolate the contained bulk material from direct contact with the woven fabric and to prevent contamination of the contained bulk material. Such liners are typically disposed of after use. Since the woven fabric material has no inherent rigidity, for dry or fluidized products that require a more rigid drum container for stability or stacking strength, solid support inserts may be placed inside the woven fabric container or slid into individual sewn pockets in the internal fabric wall of the drum container. Because of the cost of sewing operations during manufacture and the costs of any rigidity enhancing inserts used in these types of containers, they typically result in a more expensive container than the corrugated drum containers. However, if used without significant rigidity supports to hold and store liquid materials, the woven fabric container acts like a large water balloon, thereby making these types of containers more practical for use in shipping and storing dry bulk products instead of liquid or semiliquid materials. Further, the inserts that are typically placed within the woven fabric containers to provide sidewall rigidity are generally sleeves joined or hinged at their adjoining edges, to fold flat when not in use, and do not have bottoms. Without rigid bottoms, the inserts are susceptible to significant deformation from their intended footprint configuration during loading of the drum container or from subsequent shifting of the contained bulk material during transport, resulting in a misshaped containment system that is unstable before and during shipment. To address this problem, separate solid bottoms can be inserted into the fabric container or attached to the outside surface of the base of the drum container with adhesive or sewing, thus adding additional cost to the container. It is a common industry practice to use corrugated cardboard/paper inserts for rigidity. As with the corrugated containers, such inserts are susceptible to degradation and deformation when subjected to moisture or environments of high humidity. If wood or plastic inserts are used, further cost is added to the construction of the woven fabric type of drum container. The 55-gallon size woven fabric drum container can only be moved using the sewn-in slings. It cannot be tilted or rolled to another location like a rigid 55-gallon drum container.
The 55-gallon fiber, plastic, or metal drum containers have cylindrical walls, bottoms, and tops of rigid construction and do not collapse to a flat configuration. They differ in the types of materials from which they are made. The metal drums are typically constructed of steel material. Because of the materials from which these types of drum containers are made, they all overcome, with a significant degree of margin and reliability, the disadvantages of the corrugated and woven fabric drum containers with respect to stacking strength and bulge resistance. They also are generally impervious to moisture or humidity. However, the materials used to manufacture the entire drum surface are more costly than those of the corrugated or woven fabric containers, especially for the steel and plastic versions of these rigid containers. The fiber drum base material is paper. However, it is an industry common practice to poly coat the insides of the fiber drums to provide the fiber drums with more consistent and enhanced strength characteristics when subject to humidity and moisture laden environments, as compared to the corrugated containers.
Because of the rigidity of the fiber, plastic, and metal containers, they do not collapse to a flat configuration, and the storage and shipping costs are considerably higher as compared to the collapsible corrugated and woven fabric drum containers. Such shipping costs are incurred both before and after use of the rigid containers. The considerable higher shipping costs are due to the fact that their rigidity causes them to take more space in a transport vehicle as compared to the collapsible drum versions. In many cases, although a rigid drum is capable of being used a number of times, the costs of shipping the empty containers after use makes it infeasible to reuse the drum due to the expense that would be required to ship the empty containers back to a bulk material loading facility. Further, if cleaning of the containers for reuse becomes necessary, because of their rigidity and solid bottoms, additional cleaning processes and steps are required, resulting in higher costs associated with their use. Further, the costs of disposing of rigid type drum containers is greater than that of the collapsible versions since the rigid containers are more difficult to break down and need to be crushed, particularly the steel version.
The present invention addresses the above problems and shortcomings of the prior drum container bulk material containment approaches. The present invention combines and takes advantage of the strength, flexibility, recyclability and reusability features of the polypropylene materials used in the woven fabric drum containment approach, with the greater stacking and bulge strength features of the rigid fiber, plastic and metal drum container approaches. The invention provides a highly reliable container assembly for bulk materials that is rapidly configurable between an operable upright assembled configuration and a compact collapsed configuration. In its collapsed configuration, the container components are protected within a compact module that is ideal for shipping, storage, and handling and also minimizes damage to and loss of component parts of the container.